Monte Carlo Testing of Unresolved Resonance Treatment for Fast and Intermediate Critical Assemblies

Conference · Mon Oct 05 00:00:00 EDT 1998

OSTI ID:307909

Weinman, J. P. ^[1]

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1. Knolls Atomic Power Labatory, Schenectady, NY (United States)

The purpose of this study is to investigate the eigenvalue sensitivity to changes in unresolved resonance treatment by comparing RACER Monte Carlo calculations for several fast and intermediate spectrum critical experiments. Calculations performed using smooth, dilute-average, tabulated cross sections were compared with calculations using the probability table method to produce stochastically generated resonance cross sections in the unresolved resonance region. The use of the probability table method is superior to the dilute-average cross section method for representing the unresolved resonance region because the table method properly accounts for resonance self-shielding; thereby, reducing the effectiveness of the cross sections in the region. The unresolved resonance region is typically found in the intermediate and fast energy range. Eleven benchmark critical assemblies that span a range of ²³⁵U enrichments (93.8 to 10.2%) and four highly enriched ²³⁹Pu and ²³³U assemblies were analyzed. These benchmarks were chosen to accentuate the reactivity importance of the unresolved resonance range.

• Research Organization: Knolls Atomic Power Labatory, Schenectady, NY (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP)
• DOE Contract Number: AC12-76SN00052
• OSTI ID: 307909
• Report Number(s): KAPL-P--000089; K--98083; CONF-981003--; ON: DE99001567
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
97 MATHEMATICS AND COMPUTING
BENCHMARKS
Benchmarks
COMPARATIVE EVALUATIONS
EIGENVALUES
ENRICHED URANIUM
Eigenvalue Sensitivity
FAST NEUTRONS
MULTIPLICATION FACTORS
Nuclear Criticality Safety Program (NCSP)
PLUTONIUM 239
R CODES
RACER Monte Carlo Calculations
REACTIVITY
RESONANCE
URANIUM 233
URANIUM 235
ZERO POWER REACTORS